1. Field of the Invention
This invention relates to turbo-machines. More particularly the invention relates to connecting means between two cylindrical members, one lying within the other, the members being fixed with respect to one another both parallel to their axes and rotationally. More particularly the invention relates to securing a labyrinth seal on a shaft of a turbo-machine.
2. Summary of the Prior Art
The operation of turbo-machines involves the use of fluids at different pressure levels between zones separated by coaxial members which are rotatable relative to one another which are the source of leakage flows from the high to the low pressure zone at the fluidtight seals. The quality of such fluidtight seals is critical for the performance of the turbo-machine because the leakage flows are important in that they have a direct effect on the overall efficiency of the machine and in particular on the specific consumption of fuel.
Such seals, when they are of the labyrinth type, are constituted by a series of teeth or lips of annular form lying parallel to one another on the periphery of one of the members which is movable with respect to the other, the edge of each lip defining a predetermined clearance with a fluidtight surface provided on the other member.
The lips are liable to wear or deterioration when they inadvertently rub on the fluidtight surface during operation. It is therefore necessary to repair them or replace them.
In instances where the labyrinth seals are mounted on the shaft or on the drum of the corresponding turbomachine, the lips were generally provided by machining from the solid so that it is not possible to replace the lips other than by changing the shaft completely. For this reason it is preferred to machine the lips in thick cylindrical members which are secured on the shaft by bolting or other means. It is thus possible to replace these cylindrical members and readily to repair them when it is necessary.
In current engines, however, it is desirable to reduce the number of bolted connections within the enclosures of the engine of which one wall is constituted by a rotary member, because the fluid friction effect of the bolts within the enclosure gives rise to flow disturbances, and internal heating up, which is undesirable from the point of view of the strength of the members affected.
One object of the present invention is to provide securing means for a fluidtight seal in the form of a cylindrical member on a turbo-machine shaft, of which no part will itself create a flow disturbance or form a protuberance giving rise to heating up by frictional action on the ambient medium.